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(No-Model.)

e. R. EVANS v GONGENTRATOR AND AMALGAMATOR. I No. 291,997. 9 Patented Jam 15, 1884.1

UNITED STATies PATENT @rrrce.

GEORGE n. EVANS, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO JOHN P. COUCH AND WILLIAM r. ONEALE, BOTH or SAME PLACE.

CONCENTRATOR AND AMALGAMATOR.

SPECIFICATION forming part of Letters Patent No. 291,897, dated January 15, 1884. Application filed September 7, 1883. (No model.)

To all whom, it may concern.-

Be it known that I, GEORGE R. EVANS, of the city and county of San Francisco, State of California, have invented a-n Improved Concentrator and Amalgamator; and I hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to an apparatus for concentrating the precious metals or valuable 1o sulphurets from the lighter and valueless portions of a body of material which is caused to flow over its surface, and for amalgamating and arresting the gold or silver which is thus brought into contact with it; and it consists of a sluice box or trough having its bottom formed into peculiar curves or riffles, over which is fitted an amalgamated metallic surface, upon which the gold or silver will be caught, as will be more fully explained by reference to the accompanying drawings, in

which Figure l is a perspective View. Fig. 2 is a longitudinal vertical section. Fig. 3 is an enlarged view of one section of the riffle. Fig.

2 5 4 is a transverse section of the same.

A A are the sides of a box or sluice, which may be made of any convenient or desired length and width. The bottom B of this sluice may be made of metal or wood. In the prescut case I have shown it made of wood, having its upper surface formed in a series of fiat and curved surfaces, upon which the amalgamated metallic plate may be fixed and supported. The first portion, a, of each section is made flat, and the sluice is set at such an angle that while it declines from the receiving to the discharge end these surfaces a will lie nearly or quite level. Continuing from the edge of a, the surface makes a concave 4O sweep, so as to form a long shallow curve, I), and from the termination of this the surface rises into a convex curve, 0, which extends down and terminates abruptly and nearly vertically upon the next plane surface a. In this manner a succession of these surfaces a I) care formed,which continue to the end of the sluice. Upon this bed is fixed the metallic surface or plate, which may be of silver, amalgamated copper, or iron properly prepared and amalgamated. The metal plate is slightly wider than the bottom B, so as to project beyond its edges, and when the sides A are driven on and secured these edges extend into the sides, so as to form a perfectly tight joint, as shown in Fig. 4..

The operation will then be as follows: The pulp, tailings, or material containingthe precious metal, being admitted to the sluice with a sufficient amount of water, falls upon the first plane surface a, where the gold and heav- 6o ier particles sink to the bottom, and the flow is retarded because the surface is level. From this the flow increases through the concave portion 1), and this forms a sort of riffle, in which there is a forward current upon the 6 5 top, and an eddy or return-current at thebottom, which throws the fine gold back upon the first part of the curve I), where the greater portion will be found amalgamated. The coarser or heavier portions will be detained and amalgamated in the lower part of the curve b, while the light material will flow over the con vex portion 0, and fall nearly vertically upon the succeeding plane surface a, this latter action projecting the heavier particles at once to the bottom and in contact with the amalgamated surface a. The action is thus continued through as many series as the length of the sluice admits, and results in a very perfect concentration and amalgamation.

I am aware of the patent to G. Dean, March 13, 1883, N o. 27 3,969, amalgamators, in which he uses a series of drawers placed ina frame, so that each drawer will rest upon the top of another, and thus form a channel having 8 5 curved ends from one end of the machine to the other, and,further,in forming the drawers out of two pieces of channel-iron, which forms the sides, between which amalgamated corrugations are placed and secured by clamping- 9o bolts, and also in placing a feed or hopper on the top of said frame. I am also aware of the patent to O. D. Bigelow, April 3, 1883, No. 275,325, amalgamator, which simply shows a means of separating particles of gold or sil- 5 ver from the pulp, which is effected by screens of different meshes, which, being confined in separate sluiceboxes with an amalgamated plate, each sluice box being vibrated independently, and arranged in oppositely in- 0 box or trough having its bottom formed of a series of plane, concave, and convex surfaces, over which is fitted an amalgamated metallic surface, upon which the gold and sil ver will be caught as it passes from one end of the inclined sluice-box to the other.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. A riffle or sluice having the sides A and the amalgamated metallic bottom or floor, consisting of the alternate plane, concave, and convex surfaces a b c, succeeding each other, substantially as herein described. 1

2. In a sluice, the sides A and the bottom B, having an amalgamated metallic floor or surface, consisting of the alternate plane, concave, and convex surfaces 04 b c, succeeding each other, the edges of which project, so as to enter grooves in the sides and form a tight joint, substantially as herein described.

In witness whereof I hereunto set my hand.

GEORGE R. EVANS.

\Vitnesses:

G. W. EMERSON, S. H. NoURsn. 

